With the development of display technology, flat display devices like liquid crystal display (LCD) having advantages of high picture quality, energy saving, slim design and wide range of applications, are widely used in mobile phones, televisions, personal digital assistants, digital cameras, laptops, desktop computers and other consumer electronics products, thereby becoming the predominant display devices.
Most of the liquid crystal display devices on the market are back light type liquid crystal displays, which comprise liquid crystal display panels and back light modules. A liquid crystal display panel is composed of a color filter (CF) substrate, a thin film transistor (TFT) array substrate, liquid crystal (LC) sandwiched between the color film substrate and the array substrate, and a sealant frame. Among them, the performance of the thin film transistors of the array substrate directly affects the display quality of the liquid crystal display panel.
A thin film transistor using indium gallium zinc oxide (IGZO) semiconductor is provided with high mobility, thereby reducing the power consumption and cost of the liquid crystal display panels, and improving the resolution of the liquid crystal display panels to achieve full HD, and even to ultra definition (4 k*2 k) level. For that reason, such thin film transistor has received extensive attention and has been widely used. However, as the indium gallium zinc oxide semiconductor is sensitive to most of the acidic etchant and is easily corroded during wet etching, resulting in poor performance of the device.